Continuous proof and bake apparatus having improved conveyor system

ABSTRACT

A conveyor system (28-30) includes a track (110) and a conveyor chain (70) for movement along the track. The conveyor chain comprises a plurality of identical links (72) each including a first connection member (74), spaced, parallel, longitudinally extending plates (76) and a second connection member (78). The plates are connected to the connection members for pivotal movement about vertical axes, and the connection member of adjacent links are connected to each other for pivotal movement about horizontal axes thereby accommodating horizontal and vertical flexure of the conveyor chain. The conveyor chain (70) is actuated by a drive mechanism (180) including a drive chain (198) and chain engaging members (206) carried thereby which engage the conveyor chain along an arc having a substantial radius, thereby propelling the conveyor chain through the track (110) without subjecting the conveyor chain to periods of high acceleration.

This is a divisional of application Ser. No. 07/127,372 filed Dec. 2,1987.

TECHNICAL FIELD

This invention relates generally to continuous proof and bake apparatusfor use in bakeries and similar applications and more particularly to animproved conveyor system which is particularly adapted to use incontinuous proof and bake apparatus.

BACKGROUND AND SUMMARY OF THE INVENTION

In the commercial baking industry, the term "proofing" refers to theprocedure of exposing dough products to a predetermined temperature andhumidity environment and thereby causing the dough to rise. Apparatusfor accomplishing this function is generally referred to as a proofingbox or proofer. Following the proofing operation, the dough products aretransferred to an oven for baking.

Traditionally, the proofing and baking functions have been entirelyseparate steps. More recently, various manufacturers have introducedcontinuous proof and bake apparatus wherein dough products aretransferred directly from the proofer to the oven. Although the varioustypes of proof and bake appartus that have been used heretofore havereceived commercial acceptance, a need exists for still furtherimprovements in the art. In particular, improvements relating to theconstruction and operation of conveyor systems utilized in continuousproof and bake apparatus are required in order to provide improvedreliability and reduced maintenance costs.

The present invention comprises a conveyor system particularly adaptedfor use in continuous proof and bake apparatus which fulfills theforegoing and other requirements long since found wanting in the priorart. In accordance with one aspect of the invention, the conveyor systemincorporates a conveyor chain comprising a plurality of identical linkseach including first and second connection members and spaced, parallel,longitudinally extending plates. The plates are joined to the connectionmembers by vertically disposed pins to facilitate horizontal flexure ofthe conveyor chain, and the connection members of adjacent links arejoined by horizontally disposed pins to permit vertical flexure.Vertically disposed rollers are mounted on the first. connection memberof each link, and a horizontally disposed roller is mounted between theplates of each link. The rollers facilitate the movement of the chainthrough an elongate track characterized by a bottom wall, spaced apartside walls and a top wall having a longitudinally extended slot formedtherein.

One of the longitudinally extending plates of each link of the chain ispositioned on the outside of the track and serves to prevent debris fromentering the track through the longitudinally extending slot. Each linkof the chain carries a product supporting grid which is connected to thechain by means of a cover member extending between the longitudinallyextending plates of adjacent links of the chain for cooperationtherewith to prevent debris from entering the track. Each productsupporting grid comprises a pair of transverly extending rods secured tothe cover member and a W-shaped rod supported on the transverselyextending rods to provide a bakery pan support surface. Each productsupporting grid is provided with a rocker which serves to retain bakerypans in engagement with the grid during movement thereof along the trackunder the action of the conveyor chain.

In accordance with another aspect of the invention, the conveyor chainis actuated by a drive mechanism including a drive motor which isdrivingly connected to a drive chain through a speed reducer. The drivechain engages the conveyor chain along an arc characterized by a verylarge radius. In this manner power is transfered from the drive motorthrough the speed reducer and the drive chain to the conveyor chainwithout causing the conveyor chain to experience periods of rapidacceleration which are characteristic of prior drive chain designs.

DESCRIPTION OF THE DRAWINGS

A more complete understanding of the invention may be had by referenceto the following Detailed Description when taken in conjunction with theaccompanying Drawings wherein:

FIG. 1 is a perspective view of a continuous proof and bake apparatusincorporating the invention;

FIG. 2 is a transverse sectional view of the oven of the continous proofand bake apparatus showing the construction thereof.

FIG. 3 is an illustration of the construction of part of the proofer ofthe apparatus of FIG. 1;

FIG. 4 is an exploded partial perspective view of the conveyor system ofthe continuous proofing and baking apparatus of FIG. 1;

FIG. 5 is an enlarged partial exploded view similar to FIG. 4;

FIG. 6 is a partial top view of the conveyor apparatus;

FIG. 7 is a sectional view taken along the line 7--7 in FIG. 6 in thedirection of the arrows;

FIG. 8 is a sectional view taken along the line 8--8 in FIG. 6 in thedirection of the arrows;

FIG. 9 is a side view of the apparatus used to connect adjacent sectionsof the track of the conveyor apparatus of FIGS. 4 and 6;

FIG. 10 is a partial side view of the conveyor system illustrating thedrive mechanism thereof;

FIG. 11 is a view taken along the line 11--11 in FIG. 10 in thedirection of the arrows illustrating the operation of the drivemechanism;

FIGS. 12a, 12b and 12c are illustrations of the operatingcharacteristics of various types of conveyor drive systems;

FIG. 13 is an illustration of the apparatus utilized to operate theportion of the tract that is used to induce tension in the conveyorchain

FIG. 14 is an end view illustrating the operation of the chaintensioning mechanism;

FIG. 15 is an enlargement of a portion of FIG. 13;

FIG. 16 is an exploded view of the conveyor chain lubricating mechanismutilized in the conveyor system of FIGS. 4 and 6;

FIG. 17 is a sectional view taken along the line 17--17 in FIG. 16 inthe direction of the arrows.

DETAILED DESCRIPTION

Referring now to the Drawings, and particularly to FIG. 1 thereof, thereis shown a continuous proof and bake apparatus 20 incorporating thepresent invention. The continuous proof and bake apparatus 20 includes aproofer 22 wherein dough products carried on conventional bakery pans 24are exposed to a predetermined temperature and humidity environment,thereby causing the dough to rise. The continuous proof and bakeapparatus 20 further includes an oven 26 which receives the doughproducts from the proofer 22 which function to bake the dough products.

The proofer 22 includes a conveyor system 28, and the oven 26 includes aconveyor system 30 each constructed in accordance with the presentinvention. A plurality of transfer conveyors 32 are utilized toinitially place the bakery pans 24 onto the conveyor system 28, totransfer the bakery pans 24 from the conveyor system 28 to the conveyorsystem 30, and to finally remove the bakery pans 24 from the conveyorsystem 30. Each transfer conveyor 32 comprises spaced apart belts 34extending from a level substantially above the plane of the conveyorsystems 28 and/or 30 to a level substantially below the plane of theconveyor system, thereby implementing the transfer of bakery pans to andfrom the conveyor systems 28 and 30.

As is typical in continuous proof and bake appartus, the conveyor system28 travels in a spiral path through the proofer 22 and the conveyorsystem 30 travels in a spiral path through the oven 26. Referring toFIG. 2, the proofer 22 and the oven 26 each comprise side walls 40 and atop wall 42 extending there between. A plurality of ladders 44 arelocated within the proofer 22 and within the oven 26 and serve tosupport the conveyor systems 28 and 30 thereof. Each ladder 44 comprisesa pair of spaced apart up-rights 46 and a plurality of cross members 48which support the conveyor system thereon. The ladders 44 also supportbeams 50 which support the roof 42. Particularly in the case ofgas-fired ovens, the roof 42 is loosely supported on the beams 50 sothat in case of an explosion the roof can simply move upwardly torelease the resulting pressure surge and thereby minimizing damage tothe component parts of the continuous proof and bake appartus 20. Angles43 prevent the loosely supported roof from moving in a horizontal plane,while allowing the roof 42 to move upward in the event of an explosion.

As is best shown is FIG. 3, the proofer 22 comprises side walls 40formed from panels 52 each comprising metal exterior surfaces 54 and acore 56 formed from a thermally insulative material. Because of the highhumidity conditions that are typically maintained in a proofer,condensation often occurs during or following the operation thereof. Forthis reason it has been found to be advantageous to support the walls 40of the proofer 22 on concrete curbs 58 thereby eliminating the corrosionthat might occur if the panels 52 were exposed to condensationaccumulating on the floor 60 of the proofer 22. The panels 52 aresecured to the curb 58 by brackets 62 and are preferably interconnectedby means of tongue and groove joints.

The construction of the conveyor system 28 of the proofer 22 isillustrated in FIGS. 4 through 7, inclusive, it being understood thatthe conveyor system 30 of the oven 26 is identical in construction andoperation to the conveyor system 28. The conveyor system 28 includes aconveyor chain 70 comprising a plurality of idential links 72 which areconnected end to end to form the chain 70. Each link 72 comprises afirst connection member 74 situated at one end thereof a pair of spaced,parallel, longitudinally extending plates 76, and a second connectionmember 78 located at the opposite end thereof.

The first connection member 74 of each link 72 comprises spaced,parallel, upper horizontally disposed bosses 84, a lower horizontallydisposed boss 86, a vertically disposed boss 88 situated at one endthereof and an aperture situated at the opposite end thereof. Thespaced, parallel, longitudinally extending plates 76 of each link 72 aresecured to the first connection member 74 thereof by a pin 92 which isreceived through apertures 94 formed in the spaced, parallel,longitudinally extending plates 76 and an aperture 96 formed in the boss88 of the first connection member 74.

The second connection member 78 of each link 72 comprises a vertiallyoriented boss 98 and a pair of longitudinally extending arms 100extending from the boss 98 and having aligned apertures 102 formedtherein. A vertically oriented pin 92 is received through alignedapertures 94 formed in the spaced, parallel, longitudinally extendingplates 76 and in an aperture 104 extending through the verticallyoriented boss 98 to secure the second connection member 78 to thespaced, parallel longitudinally extending plates 76. The use of thevertically oriented pins 92 to connect the spaced, parallel,longitudinally extending plates 76 to the connection members 74 and 78allows the chain 70 to flex in the horizontal plane.

The conveyor chain 70 is assembled by positioning the portion of eachfirst connection member 74 having the aperture 90 formed therein betweenthe longitudinally extended arms 100 of the second connection member 78of the next adjacent link 72. A horizontally disposed pin 106 is thenextended through the aligned apertures 102 of the second connectionmember 78 and the aperture 90 of the first connection member 74, therebysecuring adjacent links 72 of the conveyor chain 70 one to the other.The use of the horizontally disposed pin 106 to connect adjacent links72 of the chain 70 allows flexure of the conveyor chain 70 in thevertical plane.

The conveyor chain 70 travels through a track 110. To facilitate themovement of the conveyor chain 70 through the track 110, each link 72 ofthe conveyor chain 70 is provided with a pair of vertically disposedrollers 112 and a horizontally disposed roller 114. The verticallydisposed rollers 112 are secured to the first connection member 74 by apin 116 which is received through apertures 118 formed in the verticallydisposed rollers 112 and an aperture 120 extending through the lowerhorizontally disposed boss 86 of the first connection member 74. Thehorizontally disposed roller 114 of each link 72 is secured between thespaced, parallel, longitudinally extending plates 76 thereof by a pin122 which is received through aligned apertures 124 formed in thespaced, parallel, logitudinally extending plates 76 and an aperture 126extending through the horizontally disposed roller 114.

Refering to FIGS. 6, 8 and 9, the track 110 comprises a series ofsections 130 which are connected end to end. Each section 130 of thetrack 110 has a horizontally disposed bottom wall 132 extending tospaced apart, vertically disposed side walls 134. The verticallydisposed side walls 134 in turn extend to horizontally disposed top wallportions 136 which are separated by longitudinally extending gap 138.

FIGS. 8 and 9 illustrate the interconnections between adjacent sections130 of the track 110. A bracket 140 is secured to one of the crossmembers 48 of one of the ladders 44 by suitable fasteners. The bracket140 supports a U-shaped connection member 142 which extends between theend portions of adjacent sections 130 of the track 110. The U-shapedconnection member 142 has outwardly turned flanges 144. Top plates 146are secured to the outwardly turned flanges 144 of the U-shapedconnection member 142 by fasteners 148 and function to clamp the endportions of the sections 130 in engagement with U-shaped connectionmember 142. An elastomeric gasket 150 is trapped between the endportions of the sections 130 of the track 110 and the U-shapedconnection member 142. The function of the elastomeric gasket 150 is toprevent lubricant contained within the track 110 from leaking ontobakery products carried on lower tiers of the track 110.

Referring again to FIG. 4, the function of the conveyor chain 70 is tocarry product supporting grids 152 along the track 110. All of thecomponents of each link 72 of the conveyor chain 70 are contained withinthe track 110, with the exception of one of the spaced, parallel,longintudinally extending plates 76 and the spaced, parallel, upperhorizontally disposed bosses 84. The upper plate 76 of each link 72 ispositioned above the top wall portions 136 of the track sections 130 andtherefore serves to prevent debris from entering the track 110 throughgap 138. As is best shown in FIG. 7, each of the product supportinggrids comprises a cover member 154 which serves to connect the productsupporting grid 152 to the spaced, parallel, upper horizontally disposedbosses 84 of one of the first connection member 74 of the link 72. Thecover members 154 extend between and overlap the spaced, parallellongitudinally extending plates 76 of adjacent links 72 for cooperationtherewith to prevent debris from entering the track 110. The covermember 154 and the bosses 84 are secured together by fasteners 156 whichextend through apertures formed in the cover members 154 and apertures158 formed in the spaced, parallel, upper horizontally disposed bosses84.

Each product supporting grid 152 further comprises transverselyextending rods 160 secured to the cover members 154. A rod 162 bent intoa W-shaped configuration is in turn supported on the transverselyextending rods 160. Each product supporting grid 152 includes a rocker164. Comprising a rod bent into a rectangular configuration as isillustrated in FIG. 4, the rocker 164 may be secured to the rod 162 byforming downwardly extending portions 166 in the rod 162 and utilizingbrackets 168 to secure the rocker 164 in engagement therewith. Analternative contruction is illustrated in FIG. 7 wherein the brackets168 which secures the rocker 164 in engagement with rod 170 are attachedto the underside of the transversely extending rods 160.

The function of the rocker 164 is to retain bakery pans in engagementwith the product supporting grid 152 during movement thereof along thetrack 110. In the case of a bakery pan having an even number ofcompartments, the rocker 164 is positioned as illustrated in FIG. 7. Oneof the compartments of the bakery pan engages the offset portion of therocker 164, thereby forcing the center portion upwardly into the gapbetween the centermost compartments of the bakery pan 24. In the case ofa bakery pan 24 having an odd number of compartments, the compartment inthe center thereof engages the centermost portion of the rocker 164thereby forcing the offset portion upwardly into the gap extendingbetween offset compartments of the bakery pan 24. In this manner asingle rocker configuration can be utilized to secure any conventionalbakery pan 24 in engagement with the product supporting grid 152.

Referring now to FIG. 10, the track 110 comprises a series of tiers 176.The conveyor chain 70 is driven by a drive system 178 comprising aplurality of conveyor drive mechanisms 180. The drive mechanisms mayengage the conveyor chain 70 at any selected tier 176 depending on thepower requirements of the conveyor system. The conveyor drive mechanisms180 are supported on shelves 182 which in turn are supported by uprights184 and interconnected by cross-braces 186.

As is best shown in FIG. 11, each conveyor drive mechanism 180 includesa drive motor 190. A speed reducer 194 drivingly connects the output ofthe drive motor to a drive sprocket 196. A drive chain 198 isconstrained around a course defined by the drive sprocket 196, idlersprockets 200, a guide member 202, and a chain tensioner 204. The drivechain 198 carries a plurality of chain engaging members 206 which areconfigured and positioned to engage the conveyor chain 70 atpre-determined points thereon, preferably the points at which the pins122 extend through the spaced, parallel, longitudinally extending plates76 of the links 72. Thus, upon actuation, the drive motor 190 operatesthrough the speed reducer 194, the drive sprocket 196, the drive chain198 and the chain engaging members 206 to propel the conveyor chain 70through the track 110.

The drive mechanism 180 further includes a lubrication system 210. Thelubrication system 210 directs a lubricant spray onto the drive chain198 through a nozzle 212. The lubrication system 212 also functions toprovide lubricant to the idler sprockets 200 and the chain tensioner204.

The idler sprockets 200 are positioned in a substantially spaced apartrelationship with respect to the track 110. The guide member 202 definesa radius of curvature R which is preferably about 14 feet. Thisconfiguration for engagement between the drive chain 198 having thechain engaging members 206 mounted thereon and the conveyor chain 70 hasbeen found to be highly advantageous in the practice of the invention.

Referring to FIGS. 12a, 12b and 12c, the drive chain/conveyor chainarrangement of the present invention is illustrated in FIG. 12a. Twoprior art drive chain/conveyor chain arrangements are illustrated inFIGS. 12b and 12c. In FIG. 12b there is shown a drive chain/conveyorchain arrangement whereby a ramped cam 214 extends between sprockets216. In FIG. 12c the drive chain engages the conveyor chain along astraight line extending between sprockets 218.

The drive chain/conveyor chain arrangement of the present invention asillustrated in FIG. 12a provides for a gradual acceleration of theconveyor chain through a relatively long interval 220. The drivechain/conveyor chain arrangement of FIG. 12b provides greateracceleration through a relatively short interval 222, resulting inerratic conveyor chain operation. Likewise, the drive chain/conveyorchain arrangement of FIG. 12c provides for more rapid accelerationthrough the short interval 224, again resulting in erratic conveyorchain operation. It has been found that erratic conveyor chain operationcaused by the drive chain/conveyor chain arrangements of FIGS. 12b and12c lead to conveyor chain breakdown causing unnecessary downtime of theoverall system and high maintenance costs.

It will be appreciated that the conveyor systems 28 and 30 of theproofer 22 and the oven 26, respectively, are at substantially highertemperatures when the continuous proof and bake apparatus 20 isoperating as compared with periods of non-operation. FIGS. 13, 14 and 15illustrate a system 230 for accomodating thermal expansion of thecomponent parts of the conveyor systems 28 and 30. A pair of fluidpowered cylinders 232 are mounted on a subframe 234 each cylinder 232has a piston rod 236 extending therefrom. Chains 238 extend from thepiston rods 236 around sprockets 240 and 242. The chains 238 are in turnconnected to curved end portions 244 of the track 110.

Referring specifically to FIG. 14, a chain 246 is constrained aroundsprockets 248 and 250. The sprocket 250 is connected to sprocket 242 atone end of the system 230 and the sprocket 248 is connected to sprocket240 at the opposite end thereof. The function of the chain 246 is toconstrain both ends of the curved end portion 240 of the track 110 toidentical movement. Movement of the curved end portion 244 is furtherconstrained by a guide member 252 which engages the curved end portion244 at the center thereof. Thus, upon operation of the cylinders 232,the curved end portion 244 of the track 110 may be moved inwardly oroutwardly to accomodate thermal contraction or thermal expansion of thecomponent parts of the conveyor system.

FIGS. 15 and 16 illustrate a system for lubricating the conveyor chain70. A U-shaped chamber surrounds a portion of the track 110. TheU-shaped chamber 260 supports a plurality of lubricant discharge nozzles262. A plurality of apertures 264 are formed through the track 110 atpoints aligned with the discharge from the nozzles 262. Lubricant isdirected to the nozzles 262 from a manifold 266 which in turn receiveslubricant from a supply line 268. The system is actuated by means ofcompressed air received through a line 270. The orientation of theconveyor chain 70 relative to the lubrication system is illustrated inFIG. 16.

From the foregoing it will be understood that the present inventioncomprises a conveyor system that is particularly adapted for use inconjunction with continuous proofer oven apparatus to providesubstantial advantages over the prior art. In particular, conveyorsystems incorporating the present invention provide substantialimprovements in reliabiity, thereby resulting in reduced maintenancecosts. Other advantages deriving from the use of the invention willreadily suggest themselves to those skilled in the art.

Although preferred embodiments of the invention have been illustrated inthe accompaning Drawings and described in the foregoing DetailedDescription, it will be understood that the invention is not limited tothe embodiments disclosed, but is capable of numerous rearrangements,modifications and substitutions of parts and elements without departingfrom the spirit of the invention.

We claim:
 1. In a system for processing bakery products, an enclosurecomprising;a plurality of vertically disposed sidewalls; a concrete curbfor supporting the side walls above the floor of the enclosure toprevent damage to the sidewalls due to accumulations of condensation onthe floor of the enclosure; a horizontally disposed top wall extendingbetween the upper ends of the side walls; means for supporting the topwall for movement along a vertical axis thereby facilitating the releaseof pressure from the interior of the enclosure in the event of aninternal explosion; a spiral conveyor system for transporting the bakerygoods through the enclosure; and a plurality of ladders, each comprisinginternal and external vertical members adjacent to the interior andexterior perimeters of the spiral conveyor connected by a plurality ofhorizontal cross members, each of said cross members corresponding to,and supporting a tier of said spiral conveyors.